my 87 needs help

[johnio69]

Guys, I have an 87 with problems. It was idleing eraticaly and i took it to a mech. He says # 4 has a miss. It has plenty of compression, is getting fire, and has feul on the plug. He put in a new plug and advanced the timing witch was seriously retarted. When you give it gas the miss stops but idle is a problem. It gets worse. It will idle for about an hour of riding, then they idle goes off the charts. It wont idle down below about 2000 rpms. The throttle cable is fine and the carb appears to be closing all the way but it still wont idle down. When it starts this, it burns mad gas. I need somewhere to start here. The mechanics around here just start replacing stuff till they get it. I need someone who can really diagnose the problem. help

 

[schmoo]

sounds like a bad vacuum leak.
if you can't see it, you may be
able to find it with an unlit
propane torch.

 

[johnio69]

the mech repaired all the vacume leaks as well

 

[johnio69]

is there anyway, i can put some kind of after market carb and intake on that doesn't rely on all the emissions crap. i'll eliminate it all

 

[olranger]

yeah going to say vacuum leak

 

[johnio69]

How would i go about finding it with an unlit torch

 

[Mark_88]

How would i go about finding it with an unlit torch

Not a good idea if you're not familiar with torches...but it will cause the engine to rev up when the propane is sucked into the engine...

You might try smoke...like a cigarette...and watch where the smoke goes...but that can be difficult with the fan blowing the air around..a squirter bottle with water in it also works...when the engine sucks in water, it should rev up a bit just like propane...

Did you replace the wire on #4 cylinder? I found one wire out a set had a break in it and caused a similar situation...replacing the wire fixed it...

 

[olranger]

get a can of carb cleaner or throttle body cleaner and start spraying hoses, it will rev up and smooth out if rough at idle, this works great.